> The book is terrible. Mark Manson is terrible.
Ad hominem.
> There is plenty of good literature
Never claimed otherwise, and it's not a zero-sum game.
> especially fiction
Sure, but different strokes for different folks, and there's something to be said about the directness of a self-help book vs. fiction.
> that doles out the same advice but in more tactful manner
His blunt voice is precisely why many find the book valuable. It cuts to the chase. The title itself makes it clear that this is what you'll get, so opening the book expecting otherwise would be nonsensical.
> rather the writings of a guy's lifetime of good fortune
His good fortune has no bearing on the value of his ideas. Again an ad hominem.